TY - JOUR
T1 - Instability of Escherichia coli R-factors in Salmonella enterica serovar Typhi involves formation of recombinant composite plasmid structures
AU - Mendoza-Medellín, Aurelio
AU - Camacho-Carranza, Rafael
AU - Curiel-Quesada, Everardo
N1 - Funding Information:
We are grateful to Irma M. Ríos Chávez for technical assistance. This work was supported by PROMEP Grant UAEMEX-EXB-01-01 , CONACYT Grant 101039 , and PAPIIT Grant IN204207 . Funding sources had no involvement in study design, collection, analysis or interpretation of data, writing of the report, nor decision to submit the article for publication.
PY - 2012/9
Y1 - 2012/9
N2 - In spite of a well-documented ability of Samonella enterica Typhi strains to receive R factors from Escherichia coli and other enterobacteria, epidemiological data show that Typhi is a rather poor host of antibiotic-resistance genes and in fact, of plasmids, suggesting that most of the plasmids naturally acquired by Typhi strains become unstable and eventually segregate. We have previously reported evidence that each of three plasmids conjugatively transferred to S. enterica Typhi experienced deletion-mediated loss of a resistance determinant before plasmid segregation occurred.We now report that in Typhi strains containing these unstable plasmids a superhelical DNA species of lower mobility is detected, probably representing plasmid dimer structures. Plasmid deletion is a RecA-dependent process since it is not detected in derivatives of a recA1 S. enterica Typhi strain containing the corresponding plasmids, and in such strains we were unable to detect either the low-mobility species. We propose that the deletable segments contain key information for plasmid stability in S. enterica Typhi, possibly a multimer resolution system.
AB - In spite of a well-documented ability of Samonella enterica Typhi strains to receive R factors from Escherichia coli and other enterobacteria, epidemiological data show that Typhi is a rather poor host of antibiotic-resistance genes and in fact, of plasmids, suggesting that most of the plasmids naturally acquired by Typhi strains become unstable and eventually segregate. We have previously reported evidence that each of three plasmids conjugatively transferred to S. enterica Typhi experienced deletion-mediated loss of a resistance determinant before plasmid segregation occurred.We now report that in Typhi strains containing these unstable plasmids a superhelical DNA species of lower mobility is detected, probably representing plasmid dimer structures. Plasmid deletion is a RecA-dependent process since it is not detected in derivatives of a recA1 S. enterica Typhi strain containing the corresponding plasmids, and in such strains we were unable to detect either the low-mobility species. We propose that the deletable segments contain key information for plasmid stability in S. enterica Typhi, possibly a multimer resolution system.
KW - Antibiotic resistance
KW - Composite plasmid structures
KW - Plasmid instability
KW - RecA recombination
KW - Salmonella enterica Typhi
UR - http://www.scopus.com/inward/record.url?scp=84862992217&partnerID=8YFLogxK
U2 - 10.1016/j.plasmid.2012.04.004
DO - 10.1016/j.plasmid.2012.04.004
M3 - Artículo
C2 - 22579995
SN - 0147-619X
VL - 68
SP - 125
EP - 132
JO - Plasmid
JF - Plasmid
IS - 2
ER -